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| author | Yegor Yefremov <yegor_sub1@visionsystems.de> | 2010-11-22 11:06:32 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-11-30 17:26:04 -0800 |
| commit | de6f86ce51341559dc3c9c9f5c562da12fcfcb31 (patch) | |
| tree | 01a51dca4ea1a201d6aa01988945d419ec84c397 /Documentation/serial | |
| parent | a4fb0b228e284107b9bdf44769bbdc80efd660e1 (diff) | |
| download | linux-de6f86ce51341559dc3c9c9f5c562da12fcfcb31.tar.bz2 | |
RS485 documentation: add 16C950 UART description
Add a notion about 16C950 UART, that is using DTR signal for RS485 mode.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation/serial')
| -rw-r--r-- | Documentation/serial/serial-rs485.txt | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt index a3b1af7b6db9..a4932387bbfb 100644 --- a/Documentation/serial/serial-rs485.txt +++ b/Documentation/serial/serial-rs485.txt @@ -11,10 +11,11 @@ 2. HARDWARE-RELATED CONSIDERATIONS - Some CPUs (e.g., Atmel AT91) contain a built-in half-duplex mode capable of - automatically controlling line direction by toggling RTS. That can used to - control external half-duplex hardware like an RS485 transceiver or any - RS232-connected half-duplex device like some modems. + Some CPUs/UARTs (e.g., Atmel AT91 or 16C950 UART) contain a built-in + half-duplex mode capable of automatically controlling line direction by + toggling RTS or DTR signals. That can be used to control external + half-duplex hardware like an RS485 transceiver or any RS232-connected + half-duplex devices like some modems. For these microcontrollers, the Linux driver should be made capable of working in both modes, and proper ioctls (see later) should be made |